This application relates to air bag assemblies for use in protection of vehicle passengers during a collision event and more particularly to a curtain air bag assembly adapted for rapid inflated deployment away from a storage position for coverage across an extended region between an occupant and a side portion of a vehicle interior.
It is well known in motor vehicles to provide air bag cushions for protection of a vehicle occupant during a collision event wherein such air bag cushions are in fluid communication with gas generating inflators so as to inflate the cushions upon sensing predetermined vehicle conditions such as deceleration exceeding a certain level. It is further known to provide air bag systems including inflatable restraint cushions which are deployed from positions of attachment along the roof rail portion of the vehicle frame above the doors of the vehicle such that the inflatable cushion extends downwardly in substantially curtain-like fashion between the occupant to be protected and the side portions of the vehicle adjacent to such occupants. Such coverage provides a cushioning restraint to the occupant during a side impact or extended roll-over collision event thereby aiding in the protection of the occupant during such events.
It is generally desirable for a curtain-like side air bag cushion to be deployed rapidly away from the roof rail in a substantially even manner. Such deployment aids in the establishment of an early effective containment barrier between the occupant to be protected and the windows or other side portions of the vehicle being covered.
In order to achieve the desired rapid uniform deployment of the curtain-like cushion a number of different techniques have been utilized. One such technique which has been utilized is to fill the cushion from an inflator disposed at one end of the cushion such as at a rearmost structural pillar of the vehicle. If desired, the uniformity of gas filling along the length of the cushion may be augmented by use of a perforated gas transmission lance along the length of the cushion. One such arrangement is illustrated and described in U.S. Pat. No. 6,135,492 to Zimmerbeutel et al. the contents of which are incorporated by reference herein. The efficiency of inflation has also been augmented by closing portions of the cushion off from inflation gas in regions where impact protection is not critical. Such configurations are disclosed in U.S. Pat. No. 6,168,191 to Webber et al. the contents of which are incorporated by reference herein. It is also known to utilize substantially vertically oriented gas conveying cells extending between the upper edge and the lower edge of the cushion. One such construction is described in U.S. Pat. No. 5,788,270 to HAland the contents of which are incorporated by reference herein.
A typical prior curtain cushion is illustrated in FIGS. 1A and 1B. As illustrated, in such prior embodiments an inflatable curtain 10 is stored in packed relation generally along the roof rail 12 of a vehicle 14 above the doors 16. The length of the inflatable curtain 10 is such that upon inflation coverage is provided over at least a portion of the distance extending along the side of the vehicle interior between two or more structural pillars 20 extending away from the roof rail 12. In the illustrated embodiment the inflatable curtain 10 is shown to be attached at the forward xe2x80x9cAxe2x80x9d pillar and at the rearward xe2x80x9cCxe2x80x9d pillar so as to cover the intermediate xe2x80x9cBxe2x80x9d pillar. In the illustrated construction the inflatable curtain 10 is inflated by a gas generating inflator 22 housed at the xe2x80x9cCxe2x80x9d pillar and connected to a gas diffuser tube 23 running along the upper edge of the curtain 10 thereby causing the curtain 10 move downwardly away from the roof rail 12. As the inflatable curtain 10 undergoes inflation, it tends to shorten as cushioning depth is developed (FIG. 1B). This shortening may be restricted by the presence of tethering straps 24 of fixed length extending between the lower edge of the inflatable curtain 10 and the forward and rearward pillars 20 bordering the area to be covered.
In the illustrated prior design, the diffuser tube is utilized to avoid preferential initial inflation of the curtain 10 at the end nearest the inflator 22. That is, the inflation gas is dispersed substantially uniformly along the upper edge across the length of the curtain 10 without regard to the location of the inflator 22. While such a construction may be effective, it has the deficiency of requiring the presence of the diffuser tube 23 which may add cost as well as requiring added storage space along the roof rail 12. As will be appreciated, in many vehicle designs such space may be limited.
The present invention provides advantages and alternatives over the prior art by providing a curtain air bag system incorporating an inflatable curtain including a gas accepting mouth feeding into a gas conveying inflatable channel extending in a path along at least a portion of the curtain perimeter. The use of a separate diffuser tube may be eliminated. In addition, the gas accepting mouth may be located at any position along the length of the curtain thereby permitting a cooperating gas emitting inflator to be housed at any location as may be desired for a given vehicle design.